A senior News of the World executive has been suspended by the paper following a "serious allegation" that he was involved with phone hacking when the paper was edited by Andy Coulson, now the prime minister's director of communications.

The News of the World confirmed in a statement that Edmondson had been suspended. It said it had launched an internal investigation into the claims and that "appropriate action" would be taken if they were found to be true.

If it is proved Edmondson also used Mulcaire's services it would destroy the paper's carefully constructed public defence that Goodman was a rogue reporter. His suspension puts fresh pressure on Coulson, who has consistently maintained that he was unaware of any hacking while editor of the paper between 2003 and 2007. Edmondson was hired by Coulson and was part of the former editor's inner circle.

It also raises embarrassing questions for the Metropolitan police, who failed to interview any News of the World executive during the Goodman/Mulcaire investigation despite the fact that the name "Ian" appears on a number of documents seized from Mulcaire.

The Guardian first revealed in July 2009 that the paper's owner, News Group Newspapers, part of Rupert Murdoch's global media empire, had paid £1m in out-of-court settlements to phone hacking victims. Since then, several people, including Miller, the Sky Sports presenter Andy Gray, former deputy assistant commissioner of the Met Brian Paddick, and Nicola Phillips, a former assistant to publicist Max Clifford, have launched legal actions against either the paper or the Met.

Miller is suing News Group, the subsidiary that publishes the News of the World, and Mulcaire, accusing them of breaching her privacy and of harassing her "solely for the commercial purpose of profiting from obtaining private information about her and to satisfy the prurient curiosity of members of the public regarding the private life of a well-known individual".

In a 20-page document lodged with the high court, the actor's solicitor, Mark Thomson, and barrister, Hugh Tomlinson, cite extracts from paperwork and other records that were seized by police from Mulcaire in August 2006. The material has been released to the lawyers on the orders of a high court judge.

The document claims Mulcaire's handwritten notes imply Edmondson instructed him to intercept Miller's voicemail and that the operation also involved targeting her mother, her publicist and one of her closest friends as well as Jude Law, her partner, and his personal assistant. During the operation Mulcaire obtained confidential data held by mobile phone companies in relation to nine different phone numbers, the notes reveal.

The document, released to the Guardian by the high court, suggests the hacking of the two actors' phones was part of a wider scheme, hatched early in 2005, when Mulcaire agreed to use "electronic intelligence and eavesdropping" to supply the paper with daily transcripts of the messages of a list of named targets from the worlds of politics, royalty and entertainment.

It also records that at the 2007 trial of Goodman it was revealed that Mulcaire wrote the word "Clive" in the top left-hand corner of his notes of hacking undertaken on Goodman's behalf. According to the high court document, Mulcaire's notes for the hacking of Miller "in several cases were marked 'Ian' in the top left-hand corner, which the claimant infers to be Ian Edmondson". Tonight, Labour MP Tom Watson said: "News International's pathetic 'it was only a rogue reporter' defence is imploding. There is now a senior executive appointed by Andy Coulson suspended on allegations of phone hacking. It is time we heard from Rupert Murdoch himself."

In its statement, the News of the World said: "The News of the World has a zero-tolerance approach to any wrongdoing."